Complementary Psalmody in the Liturgy of the Hours is the additional fixed psalm sets supplied for the daytime Hours so that Terce, Sext, and None can all be celebrated on one day without simply repeating the day's one variable psalmody three times.
Daytime Prayer has one variable and two complementary sets
The postconciliar Liturgy of the Hours provides prayer at midmorning, midday, and midafternoon, traditionally called Terce, Sext, and None. A person bound or choosing to celebrate only one of these Hours uses the current day's psalmody at whichever hour is selected. The book does not require three Hours merely because it prints all three titles.
When all three Daytime Hours are celebrated, the day's variable psalmody is used at one Hour and complementary psalmody at the other two. This arrangement preserves the four-week Psalter's movement while preventing mechanical repetition of the same three psalms. Hymn, reading, versicle, prayer, and any proper elements still correspond to the actual hour and celebration.
Complementary does not mean improvised or optional filler
The complementary psalms are approved liturgical text, traditionally drawing heavily on the gradual psalms. They are not chosen ad libitum from a personal Bible, nor are they a devotional supplement appended after the Office. If a community celebrates all three daytime Hours, the distribution rule determines where these sets belong unless a proper rubric supplies different psalmody.[1][2]
A solemnity can provide proper psalms for one daytime Hour while directing complementary psalmody at the remaining Hours. The calendar, Proper, and General Instruction must therefore be read together. Simply repeating the solemnity psalmody at Terce, Sext, and None may contradict the rubrics even though every repeated text is itself sacred Scripture.[3]
One Daytime Hour
Clerics and communities whose obligation embraces one daytime Hour select the hour that best corresponds to the real time and use the assigned variable psalmody. Complementary sets do not provide a shortcut around a difficult psalm or an alternative four-week cursus. Their purpose emerges only when more than one Daytime Hour is prayed.
All three traditional little Hours
Those who retain Terce, Sext, and None choose which one receives the day's psalmody; the General Instruction gives contextual rules, especially for solemnities. The other two use the complementary sets in the book. This is a lawful fuller observance of daytime praise, but it does not create three independent liturgical days or triple a single canonical obligation.
The rule serves truth of time and intelligible prayer
Daytime Prayer sanctifies distinct moments of work and recollection. Complementary psalmody gives repeated prayer a stable biblical vocabulary while preserving enough variety for attentive celebration. Its recurring pilgrimage imagery also links the Church's daily labor to movement toward God, without assigning an esoteric theme or guaranteed spiritual effect to a particular set.
Confusion commonly arises in apps that display one preferred Hour, in older breviaries with a different cursus, or when monastic constitutions retain several little Hours. The Roman General Instruction governs the Roman book; monastic, Eastern Catholic, and institute-specific offices may order psalmody differently under their own approved law. Complementary psalmody is therefore a precise Roman rubrical classification, not the universal name for every repeated set of psalms.
References
- 1.Laudis canticum — The apostolic constitution promulgating the revised Liturgy of the Hours and explaining the Office of Readings
- 2.Sacrosanctum Concilium — Vatican II norms on liturgical time, the Divine Office, adaptations, and pious exercises
- 3.General Instruction of the Liturgy of the Hours — The official general instruction governing the Hours, including the extended vigil form of the Office of Readings